1. Field of the Invention
The present invention relates to a rear derailleur for a bicycle having a bracket connected to a bicycle frame, a guide wheel for shifting a chain, a support member for supporting the guide wheel, a base member pivotably attached to the bracket, a tension spring for biasing the base member in a predetermined pivoting direction, and a linkage device for linking the support member and base member.
2. Description of the Related Art
In a rear derailleur for a bicycle of the type noted above, as disclosed in Japanese Patent Publication No. 47-27656, for example, the tension spring is disposed outwardly of the bracket, that is to say the tension spring is attached, in a posture extending transversely of the bicycle, to a mounting section formed on a side of the bracket facing away from the bicycle frame. Consequently, the bracket lies between the tension spring and bicycle frame.
In the construction noted above in which the tension spring is disposed outside the bracket with respect to the bicycle frame, the end of the tension spring disposed inwardly is engaged with the bracket, while the end of the tension spring disposed outwardly is engaged with the base member. It is necessary for the base member to include a section opposed to the bracket across the tension spring for engaging the tension spring. Conventionally, therefore, where the base member and bracket are connected, the base member projects to a relatively large extent outwardly from the bracket in the transverse direction of the bicycle.